The agency responsible for investigating just what happened in Charleston is the U.S. Chemical Safety Board. It's a relative newcomer to Washington. It first got to work in 1998 and was modeled after the National Transportation Safety Board, which investigates plane crashes and other transportation accidents. The Chemical Safety Board's mission is to investigate significant chemical accidents. Its current chairman is Rafael Moure-Eraso, an academic and native of Colombia. He says the issue of chemical safety in the U.S. has reached crisis proportions.

RAFAEL MOURE-ERASO: We have a chemical problem in the U.S. If these things cannot be controlled, if our water cannot be kept pristine for us to use, we have a problem.

NAYLOR: That problem is especially acute in the Kanawha Valley around Charleston, known locally as Chemical Valley. Maya Nye is with the West Virginia-based People Concerned About Chemical Safety. Nye says it's not the first time the board has been there.

MAYA NYE: This is the third time the United States Chemical Safety Board has been to this particular valley in the last five years. That's more than any other investigation that they've done in this sort of small of a proximity in any other part of the country.

NAYLOR: The CSB investigated accidents at West Virginia plants owned by chemical giants DuPont and Bayer in which a total of three workers were killed. The agency made this highly-produced video as part of the DuPont investigation.

(SOUNDBITE OF VIDEO, "FATAL EXPOSURE: TRAGEDY AT DUPONT")

BEVERLY SAMUEL: Yes, ma'am. My name is Beverly Samuel(ph). I'm at the DuPont plant in Belle, West Virginia. I need an ambulance immediately.

UNIDENTIFIED MAN #1: The DuPont safety reputation was shaken in January of 2010 when three separate incidents occurred within 33 hours at the company's manufacturing plant in Belle, West Virginia.

NAYLOR: But despite the dramatic video, the CSB's recommendations to improve safety practices in West Virginia were largely ignored by state officials. And that's one of the problems with the agency, says Noah Sachs. He's a law professor at the University of Richmond.

NOAH SACHS: The agency does not have enough staff. And on top of that, the agency can only make recommendations to state or federal governments or even to the companies themselves that have an accident. So those recommendations from the CSB, the Chemical Safety Board, are routinely ignored and not implemented.

NAYLOR: The CSB has 161 open or pending recommendations to improve safety. A 2010 inspector general's report found the CSB does not press hard enough to get those recommendations implemented. Another problem facing the CSB, it's got a lot of investigations going right now - 13 including Charleston, some dating back over four years. It's looking into major refinery accidents in Texas and Washington State and the 2010 explosion at the BP-Macondo Well in the Gulf of Mexico. CSB chairman Moure-Eraso says it takes time and money to do a thorough job.

MOURE-ERASO: We are a very small agency in which we have 21 people available to deploy for this type of thing. So we have to be playing musical chairs and moving teams from one big investigation to another. So this has as a consequence that the reports are delayed. But we are not ever going to release a report before its time.

NAYLOR: But former CSB board member, Gerald Poje, says the board's recommendations lose their impact if they are not issued until years after an accident.

GERALD POJE: An incident should be conceived of as being put to bed shortly after you begin it. Otherwise, you lose the advantage of the audience wanting to understand what happened, why and adopt the recommendations you make.

NAYLOR: The CSB's budget is about $10.5 million annually. It's been stretched by some 200 chemical accidents a year. CSB chairman Moure-Eraso won't put a timetable on how long it will take to investigate the Charleston chemical spill. Brian Naylor, NPR News, Washington. Transcript provided by NPR, Copyright NPR.